The present invention generally relates to a digital content distribution control method suitable for a system for distributing digital content such as audio data and video data for example and billing the digital content according to a usage quantity thereof, a digital content reproducing method, and an apparatus using the digital content reproducing method.
A software control method disclosed in U.S. Pat. No. 5,103,392 for example is known as an advantageous technique for simplifying the distribution of digital content such as computer programs, audio data, and video data, exploiting potential demands for digital content, and expanding the market of this field. The software control method disclosed in U.S. Pat. No. 5,103,392 is designed to indicate, in use of software such as computer programs and video data, which are intangible assets, a software usage status classified by software proprietor for example. This method is also adapted, in use of software such as computer programs and video data, which are intangible assets, to purchase programs for payment (the purchased programs can be used for free of charge) and set prices on the purchased programs. Data indicative of prices at which programs are purchasable is stored in a computer system. When purchasing programs for payment, they are registered in a table as the names of available software in this computer system. At the same time, the data indicative of purchasable prices is decremented by software prices. When deleting registered software from this table, the data indicative of purchasable prices is incrementally updated according to a situation. Further, in use of software such as computer programs and video data, which are intangible assets, in order to collect bills for usage of programs for payment according to an actual usage quantity (the number of times or the length of time in which a particular program for payment has been used, for example), the identifications of the programs used, user identifications, and program usage fees are recorded beforehand. By calling back this record, the program proprietor can grasp the usage fees of the programs owned by the program proprietor. Thus, the above-mentioned method is effective for use in collecting the bills for utilized programs according to the usage quantities thereof.
However, the above-mentioned system for distributing digital content through a network is considered to be operated only on personal computers. Therefore, there is no system that is portable with ease and provides the above-mentioned digital content anytime and anywhere.
The above-mentioned disclosed technique is advantageous in exploiting potential demands for digital content and expanding the market. However, this technique is insufficient in protecting digital content from illegal duplication or unauthorized use and provides no economical system.